The production of ice as previously practiced requires apparatus involving a variety of moving parts and devices for establishing a solid product, to harvest, and its transport to storage. Mechanical refrigeration is usually involved, by which gas is compressed, liquified and then expanded; in which the principles of evaporation are utilized to absorb heat from water and thereby transforming it into ice. The water to be frozen must be supplied in measured quantity and contained within vessels from which it is extracted as ice; a time schedule must be established for the heat absorption period, extraction period, and the vessel refill period, and all of which requires time and temperature control of the water supply and coordinated operation of the refrigeration equipment. In practice, unforeseeable variables enter into ice production in the form of atmospheric conditions, inlet water temperatures, and variations in plant efficiencies; all of which are unpredictable and require complex sensing and control means. Therefore, it is a general object of this invention to provide for minimal complexity in the process and/or operation of apparatus producing ice, and a system therefor which is inherently operable continuously at optimum efficiencies dependent upon prevailing conditions.
The present invention employs mechanical refrigeration in its basic form and combines therewith the fewest number of elements, and excepting the refrigeration means per se this invention virtually eliminates moving parts and relies upon the thermo control of refrigerant flow and product water supply. Accordingly, it is an object of this invention to provide a method that operates in reliance upon the principles of freezing, thawing and ejection of the product. With the present invention, the product cycle involves applied heat absorption to a stall filled with water and applied until iced, followed by applied heating of the stall filled with ice until the ice-to-stall interfaces are thawed and accompanied by application of water under pressure to refill said stall by floating the ice as a product therefrom, and the product cycle repeated by reinstating the applied heat absorption in place of said heating. Floatation water is recovered and reapplied as refill water to this "freeze-thaw-ejection cycle".
Quality production of ice, regardless of size, on an economical basis is an object of this invention, and to this end the aforementioned freeze-thaw ejection cycle is progressively applied to a series of stalls for the efficient and continuous production of ice. With the preferred form of the present invention, the product cycle involves progressively applied heat absorption through a series of stalls filled with water and applied until all stalls are iced, followed by progressively applied heating through said series of stalls filled with ice until the ice-to-stall interfaces are thawed and accompanied by application of water pressure to refill said stalls by progressively floating the ice as a product therefrom, and the product cycle repeated by reinstating the progressively applied heat absorption in place of said progressive heating. The progressive application of the aforementioned freeze-thaw-ejection cycle involves the heat conductive capability of a series of ice stalls cooperatively related to heat absorption and heating applied sequentially thereto.
It is an object of this invention to provide a method wherein a stall is filled with water from a pressure supply thereof and heat alternately absorbed therefrom and applied thereto, the water supply and said means being responsive to a stall temperature sensor and a control therefrom responsive to thawing and operating said means to absorb heat until the stall is iced and responsive to freezing and operating said pressure supply to apply water and simultaneously operating said means to apply heat until the stall is thawed.
It is an object of this invention to provide for continuously carrying out the method referred to, and to this end there is a series of stalls filled with water from a common pressure supply thereof and means alternately absorbing heat progressively from and progressively applying heat thereto, the water supply and said means being responsive to a selectively positioned stall temperature sensor and a control therefrom responsive to thawing and operating said means to absorb heat until the stalls are iced and responsive to freezing and operating said pressure supply to apply water and simultaneously operating said means to apply heat until the stalls are thawed.
It is still another object of this invention to provide an ice stall and water filling manifold therefor combined so as to discharge product ice by means of floatation. With the present invention the ice stall is displaced from vertical and the product ice discharged therefrom by hydraulic floatation. In addition to floatation in the strict sense, the hydraulic action involves displacement whereby the ice is ejected as a piston.
It is a further object of this invention to provide a method of the character thus far referred to that is self-sufficient and entirely automatic, with means to conserve floatation water, and to conserve operating energy when a full harvest is obtained. The harvest bin is a cold-sink for storage, while the floatation water is maintained at a constant level for accurate pressure application by means of a pump. Control is entirely by thermal response, there being a single thermostatic switch to automatically control refrigerant flow and supply water to the stalls. The harvest switch operates independently in response to the temperature of ice reaching the brim of the storage bin.